SHEN Wei1,2, Zhou Qing1,2, ZHU Run-liang1, WEI Jing-ming1, ZHU Jian-xi1

(1. CAS Key Laboratory of Mineralogy and Metallogeny, Guangzhou Institute of Geochemistry, Chinese Academy of Sciences, Guangzhou 510640, China;
2. University of the Chinese Academy of Sciences, Beijing 100049, China)

Abstract: Numerous studies have shown that organoclays can effectively adsorb hydrophobic organic contaminants and they have been considered as efficient adsorbents for the remediation of organic pollution. Understanding the adsorptive characteristics of organoclays is critical for improving their remediation efficiency. In this work, cetyltrimethylammonium cation modified montmorillonite (CTMA-Mont) was selected as a representative organoclay, and its adsorptive characteristics towards benzene molecules were studied using molecular dynamic (MD) simulations. Our results show atomic-level structure of the interlayer spaces of the water saturated CTMA-Mont. Benzene molecules were found to be adsorbed primarily in the alkyl-chain aggregates of CTMA; while a hydrophobic siloxane surface could not effectively adsorb benzene molecules because of the strong competition effect from alkyl chains. With increasing CTMA load level, the size of alkyl-chain aggregates increase accordingly, and they can provide more adsorption sites for benzene molecules, which then finally leads to enhanced sorption of benzene molecules in CTMA-Mont.

Key words: organoclay; molecular modeling; montmorillonite; adsorption; organic contaminants

E-mail: zhujx@gig.ac.cn

ACTA MINERALOGICA SINICA Vol. 34, No. 4, 2014, Page 433-438